BayHac 2018!


This week we’ll be taking a quick breather from our work on deploying our Haskell code. Instead, I’ll be giving a brief overview of BayHac, the Bay Area Haskell Hackathon, which took place a week ago from April 27-29. It was hosted once again by Formation (formerly Takt). Many Haskellers from the Bay Area and beyond met up, hacked and discussed many ideas.


This year there was a larger focus on projects and hacking, and less on presentations. But there were still a few short talks each morning. I was only able to make one set of these, but that included some very interesting topics. A couple speakers discussed some of the theoretical aspects of Haskell’s containers. One went through the idea of free objects, a generalization of free monads as seen on this blog. Another speaker discussed ways to perform type-level validation within Postgres.

And speaking of databases, Travis Athougies gave an overview of his Beam database library. This library has some awesome semantics. It might force me to re-think my habit of defaulting to Persistent, so it's definitely worth a look!

Finally, I gave a short overview of some of the work I did last year with Tensorflow and dependent types. I’ll post a link to the presentation as soon as it’s up. But in the meantime, you can check out the full blog series to learn more!

Nix and HNix

I spent most of my time at the Hackathon trying to setup Nix, so that I could work on HNix. Nix is a functional package manager with incredible reliability. We could use it for any language in theory. But it shares many conceptual ideas with Haskell, so many Haskellers have adopted it. In particular, if you do frontend web programming with GHCJS, you’ll want to use Nix instead of Stack.

Several people at the Hackathon worked on HNix, a Haskell implementation of Nix. The work was well organized by John Wiegley. He put in a lot of time parceling out tasks that newcomers could contribute to the codebase.

Having a Windows laptop, I wasn’t able to contribute a whole lot to the project (Nix only runs on *nix systems). Instead, I let myself be a guinea pig to see if I could get Nix working on the Windows Subsystem for Linux. My efforts were unsuccessful, though Jonas Chevalier of Tweag insists it’s possible.


The last talk I saw came from Chris Smith, who gave an overview of Haskell Codeworld, an educational tool for math and programming. This project in particular caught my attention for a couple reasons. First, I’ve developed a passion for teaching Haskell to beginners and showing it’s not so hard. But even I tend not to focus on teaching Haskell as a first language. Chris’s idea is to teach Haskell to middle school kids who have never written code before.

His primary intention is to teach mathematics. Since Haskell has such a mathematical view of programming, it's a natural fit. He stated an interesting finding from an academic study. Children’s success in calculus depends a lot on their understanding of functions. Those who view functions as a mere series of steps to compute tend to struggle. But there's another more correct way to view functions. This idea is that functions express a fundamental relationship between sets. Those who view functions this way have a better chance of flourishing.

This research suggests Haskell is great as a primary programming language for kids! It matches the latter definition, while object oriented languages teach the former idea. Codeworld a cool project, so check it out and see if you can help in any way!


Next week, we’ll conclude our series on deploying Haskell code by looking at Github’s API. It has some neat little tricks we can play to enhance our development experience.

Events like BayHac show that there are a lot of different ways to get involved in the Haskell community. See if you can find one in your city! And don’t worry if you’ve never written Haskell before! The Haskell community is very welcoming! Check out our Beginners Checklist to get started!